Pay per click advertising involves a Web site operator or publisher displays selectable (or “clickable”) links from advertisers. In exchange for displaying the ad, the advertiser pays the operator based on actual exposure of the ad, measured by the number of clicks on the ad. One measure used in the industry is the so called “click-through rate,” which is the ratio between the number of viewers who clicked on the ad compared to the number of users who were presented with the ad.
Although clicks and click-through rates are relatively easy to measure, they are susceptible to unscrupulous manipulation. For example, the operator of the Web site who is paid based on the number of clicks on advertising hosted by his or her site has a financial incentive to “fool” the system to increase the apparent number of clicks. This imitation of a person clicking on an advertisement through the use of a computer program or script is known as “click fraud.” Other individuals and organizations that do not have a direct financial incentive may also have some incentive to commit click fraud. For example, an organization may benefit indirectly by driving up the click rates on a competitors ads, thereby causing the competitor to expend more money for ads than warranted by actual usage. Similarly, individuals who have a grievance against an organization may also commit click fraud in order to reduce the organizations return on advertising expenditures.
Internet advertising can be quite valuable, and click-through rates, while not perfect, are still an easily quantifiable measure of an ad's success. As a result, finding new and improved ways to prevent click fraud is desirable.